The Battle of Ideas is an annual, weekend-long series of panel discussions hosted at the Barbican in London, ranging across subjects from neuroscience to music and everything in between. With a strong thread of architecture and urbanism, this year offered a spectacular chance to probe the popular trends and fads in today's design culture.

Alastair Donald - who had a prominent role either producing, chairing or speaking in a number of the sessions - told me that the spirit of the Battle of Ideas was to encourage speakers to develop novel ways of thinking about an issue. It welcomes unpopular or unusual ideas, but then practically bullies speakers into defending those ideas with clear thought and expression. It does not tolerate speakers who gloss over details, as is sometimes the case when experts speak in public.

This spirit was on display throughout both days. Members of the audience were taken on a whirlwind tour of ideas from both the center and the fringes of establishment thought.

The first session, entitled "Pop-ups: Overhyped and Everywhere?" was opened with characteristic enthusiasm by Oliver Wainwright, architecture critic for the Guardian. Wainwright lamented the shift of pop-ups from their origins as tactical, grass-roots forms of urbanism. He feels that they've become co-opted by government and capital, noting that they are usually now either a "cynical stop-gap" before the money or approval is gathered for a permanent, more profitable development, or "flimsy sticking plasters covering the weeping sores of the economic downturn".

Reinforcing Wainwright's views on the panel were Alastair Donald and Pedro Bismarck, who both saw our fascination with pop-ups as a symptom of our refusal to deal with serious political issues. Donald saw them as part of a wider "vacuum of ideas" in architecture, as architects have stopped truly believing in architecture as an agent for change. Bismarck noted the tendency for pop-ups to be designed by young architects for disadvantaged communities, and thus characterized them as "precarious structures for precarious people".

However Cany Ash of Ash Sakula Architects, speaking in favour of pop-ups, regarded their proliferation as the result of a kind of productive impatience. She noted that she personally found herself "sickened by decades of unimaginative urbanism" and reinforced the idea that pop-ups are still a viable form of grass-roots urbanism, saying that "if you don't create a kind of compost heap of experiences for people they don't know what can be done."

The pop-ups discussion might be summarized as a debate between critics and theorists who ask and expect more from architecture than what is currently being produced, and an architect on the front lines who values action, however small, above being hamstrung by an unsympathetic political and economic climate. This dichotomy was also on display in the "Masterplanning the Future" discussion: Farshid Moussavi of Farshid Moussavi Architects chose to advocate smaller and slower masterplans which adapt to the changing needs of the design whilst they are created; Malcolm Smith, a director of urban design and masterplanning at Arup, similarly rejected the idea of chasing the monumental in planning, saying we need to begin to value the everyday, reject the seduction of the image and engage in the process behind designing and implementing masterplans.

These ideas were combated this time by two academics. Theodore Dounas, an associate professor at Xian Jiaotong Liverpool University, noted how the urban explosion in China, although unprecedented and sometimes a little out of control, succeeds because the population of China trusts that it is happening in the interests of the people at large. By contrast, in the West we have "no confidence in politics and therefore no confidence in the polis itself."

Penny Lewis, a lecturer at the Scott Sutherland School of Architecture, supported this idea by saying that there is a crisis of confidence among architects and planners who are afraid to create a design which is expressive of human will. She believes that planners have grown to fear their own power, citing Luigi Snozzi, the Italian Rationalist architect, as an example of an old-school designer who does not fear the destructive impulse which often sits alongside the will to create. By contrast, architects today retreat from making too much of an impact, preferring to place faith in community participation. She concluded with the thought "do architects say 'I'm into participation too', or do they have the cojones to say 'actually as an expert I have something to add to this'?"

Another session in which architects were found to be shying away from responsibility was in "Designing Citizens: Architects as Nudgers," a session which looked into the growing trend to design spaces which make it easier to make the 'right' decision - such as a design which encourages people to take the stairs rather than the elevator, for example.

Following discussion of the problematic issues of who decides what are the 'right' choices, Henry Ashworth, a former member of the Cabinet Office's Behavioral Insights team, stated that he often encounters architects who claim not to be nudging in this way, even though he believes absolutely every decision made in design inevitably affect people's decision-making. He advocated that architects should take responsibility for their designs. He also said that 'nudging' should be "absolutely pro-choice", and architects should know the difference between offering people the chance to consider their own decision, and forcing them to do the 'right' thing by giving them only one option.

However Deputy Editor of the Architects' JournalRory Olcayto warned against the idea that architects should allow themselves to be complicit in this movement. Examining where architects realistically stand in the construction industry, he believes that architects can only ever 'nudge' behavior on behalf of their clients. This could potentially lead to a system where architects are rewarded for "positive nudging" and punished for "failing to nudge" - a system which he says would be damaging to the profession.

Interestingly, another session highlighted a trend where architects are proposing revolutionary ideas and taking responsibility for them, and questioned whether it would be capable of living up to its promise. "Grow Your Own?" was a session that investigated the increasing support for urban agriculture, a movement that has claims to solve a range of problems, both in terms of production as well as socially and culturally.

All speakers agreed that retro-fitting a city such as London to feed its entire population would be impossible, but here agreement ended. CJ Lim, a professor at the Bartlett School of Architecture, spoke in favour of a variety of forms of urban agriculture: from industrial-scale urban farms, which he argued could feed an entire city if it was planned with them from the beginning; to community-based farms and gardens which can strengthen social bonds between residents and put people back in touch with the processes of food production that we have become so alienated from.

The argument was given some perspective by agricultural experts: Anand Dossa, an economist for the National Farmers' Union, pointed out that the real challenge is "food security" : the ability of food production to be sufficient even in hard times. This security is something which the existing food industry has developed over the centuries, but he did not believe it was possible to achieve with urban agriculture. Stephen Hargrave, the chairman of London Farmers' Markets Ltd similarly mentioned that if significant food production were possible in cities, a lack of resources like soil and water would rule out romantic notions of urban agriculture, and the reality would likely be food grown in highly artificial, optimized environments.

Vicky Richardson of the British Design Council used her personal experience of city-based gardening to great effect: she argued that for her, gardening is an opportunity for some personal time, rather than as a community bonding exercise. She also mentioned that attempting to grow her own food has made her realize that subsistence farming is an incredibly precarious activity, and actually makes you marvel at the tremendous output of the food industry - and in many ways a move towards local, community grown food is incredibly anti-progressive.

This debate showcased the amazing talent of four young thinkers. Not only was opportunity pitted against the poverty big cities often bring, but there were discussions of how you might control the growth of cities and how countries like China and India might manage their enormous population growth. But one of the most arresting insights was given by Nikhil Amarnath of NPS Koramangala, who used his knowledge of his hometown of Bangalore to great effect, arguing that sustainability in cities is a "Western Preoccupation," and that developing countries should be afforded the time to catch up to western nations in terms of prosperity and quality of life, before they are restricted by the demands of sustainability.

At the Battle of Ideas, the range of topics discussed and the different backgrounds of those involved - of different ages, cultures and professions - gave for a truly refreshing intellectual experience. In recent years it has sometimes seemed that debate of architectural issues has become stagnant, relying on cliches and received wisdom, inevitably bound up within political and economic systems which are both inflexible and impossible to change. The Battle of Ideas, above all, is a reminder that the business of architecture is not as futile as it sometimes seems; everything is still up for grabs.